The cranckset shouldn't matter. When you buy the bike this should already have been considered (Compact, tripple, double). Although anyone can change his mind I opt for 2 different cassettes: 12-23 and 12-27. This works for me from racing/touring on the flat to racing/touring in the mountains

I used the wide range in the mountains and are not busy with my optimal cadence at those rides. On the flat it does bother me, but also that is very personal. That's why multiple cassettes will help out

Fortunately the difference lies just in the price of a new cassette, one that gets worn out in 6-12 months any way. So go and try it. Fact is, at 11 speed, the gaps between cogs is pretty small, and only lies in the b/n two of the larger cogs. Go and compare the exact cog teeth numbers of the two cassettes and you'll see what I mean.

Metor wrote:I used the wide range in the mountains and are not busy with my optimal cadence at those rides. On the flat it does bother me, but also that is very personal. That's why multiple cassettes will help out

What rear tooth/teeth do you like to be in on the flat to achieve your consistent cadence?

I think you can now make a well informed decision for your first trial cassette and know where exactly to monitor. At the end of the day, it's question of whether you have sufficient number of hard climbs that you need that 27.

I like close ratios, but also need to compromise a little as I'm no climber. So I use an 11-25 10sp.

If you select the 12-27, then you'll need to use the small chainring most often in order to stay on the small end of the cassette. If you try to use the big ring you'll spend a lot of time on the big end of the cassette where the ratios are wider. If you really need a ratio as low as 39x27 (38"), then a better choice would be a compact 52/36 chainring with an 11-25 cassette. This combination will give the best spread of close ratios and a 37.9" low gear. Hard to see though why you would need such a low gear at Jabiru.

Krank wrote:Why do I need to use the small chainring most often in order to stay on the small end of this 12-27 cassette, as opposed to other different geared cassettes (such as the 11-25)?

Also, how often do you use the 11t cog?

If you use the big chainring, then you need to use two gears lower (i.e. bigger sprockets) on the cassette to obtain approximately the same ratio. If your speed is under 30 kph you'll be using the big end of the cassette.

I rarely use the big ring, since 39x12 yields 37kph at 90rpm cadence. Staying on the small ring means I am most often on the small (close ratio) end of the cassette.

I do use the 11t cog when I start to spin out on the 12t and know that I won't need to hold it for very long. But the point of having the 11t is to have a usable 12.

I don't use the big ring until my speed gets up around 40kph, when I'm sure to stay on the small end of the cassette.

very good insight Ronk. You have just opened my world further into gearing (despite reading alot of stuff on the net).

I may have to re-assess the way I ride now...

I am in my large chain ring (and the smaller 3 cogs) for most of my riding (have not used the small chain ring since Perth Hills in 2011), but I notice my cadence is lower than 80RPM.

I am thinking now for me to improve I need to sustain a higher cadence, which obviously means paying more attention to my counter and responding more frequently to gear changes to maintain a stable cadence.

So, the smaller front chain ring enables a closer ratio - so obvious to me now

Can you elaborate more on making the 12t cog more usable with the 11t cog up front?

I have not yet purchased the crankset yet and the cassette because i do need to research this topic more, and I am more than happy to buy more than 1 cassette.

When I read the reviews on the Oltre XR, most users use and state the importance of using the standard crankset, and I wonder why?

RonK wrote:If you use the big chainring, then you need to use two gears lower (i.e. bigger sprockets) on the cassette to obtain approximately the same ratio. If your speed is under 30 kph you'll be using the big end of the cassette.

Yep, that's why the 50 on my CT chainset works. For regular riding, I hardly ever need to move to the small ring except for nasty climbs.

If there were no significant hills around Sydney and I am 25 years younger, I'd go with a standard. CT gives a middle aged recreation rider that extra 2 steps at the lower end with little loss at the top (11-25). That's the basic reason for me.

I use 50/34 CT On both my road bikes. Changing rear cogs for cadence is no different what chainset you use.

Krank wrote:very good insight Ronk. You have just opened my world further into gearing (despite reading alot of stuff on the net).

I may have to re-assess the way I ride now...

I am in my large chain ring (and the smaller 3 cogs) for most of my riding (have not used the small chain ring since Perth Hills in 2011), but I notice my cadence is lower than 80RPM.

I am thinking now for me to improve I need to sustain a higher cadence, which obviously means paying more attention to my counter and responding more frequently to gear changes to maintain a stable cadence.

So, the smaller front chain ring enables a closer ratio - so obvious to me now

Can you elaborate more on making the 12t cog more usable with the 11t cog up front?

I have not yet purchased the crankset yet and the cassette because i do need to research this topic more, and I am more than happy to buy more than 1 cassette.

When I read the reviews on the Oltre XR, most users use and state the importance of using the standard crankset, and I wonder why?

Krank

OK, so now you reveal that you don't use the small ring, I can understand why you want a 27t cog. However this approach makes no sense to me.

I aim to maintain an average cadence of 90 rpm. Since my usual road speed in flat, windless conditions is around 30-35kph, and I like my gear ratios to be close, then I have to use the small chainring.

On any cassette, to avoid cross chaining you don't want to use the small sprocket with the small ring, or the big sprocket with the big ring. So to have a usable 12t, you need an 11t, which will rarely be used.

Knowing now how you ride, I think your best choice would be to stick with a standard 53/39 chain set and an 11-25 cassette and start using the small chainring, bearing in mind that to achieve the recommended 90 rpm average cadence you will need to be pedaling faster than that for much of the time. I often rev up around 130rpm.

Last edited by RonK on Sat Jan 19, 2013 6:06 pm, edited 3 times in total.

RonK wrote:If you use the big chainring, then you need to use two gears lower (i.e. bigger sprockets) on the cassette to obtain approximately the same ratio. If your speed is under 30 kph you'll be using the big end of the cassette.

Yep, that's why the 50 on my CT chainset works. For regular riding, I hardly ever need to move to the small ring except for nasty climbs.

Who is online

About the Australian Cycling Forums

The largest cycling discussion forum in Australia for all things bike; from new riders to seasoned bike nuts, the Australian Cycling Forums are a welcoming community where you can ask questions and talk about the type of bikes and cycling topics you like.